python 用opencv实现霍夫线变换

import cv2
import numpy as np
from matplotlib import pyplot as plt

img = cv2.imread('img.jpg')
gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
edges = cv2.Canny(gray,50,150,apertureSize = 3)

lines = cv2.HoughLines(edges,1,np.pi/180,200)
for line in lines:
  rho,theta = line[0]
  a = np.cos(theta)
  b = np.sin(theta)
  x0 = a*rho
  y0 = b*rho
  x1 = int(x0 + 1000*(-b))
  y1 = int(y0 + 1000*(a))
  x2 = int(x0 - 1000*(-b))
  y2 = int(y0 - 1000*(a))

  cv2.line(img,(x1,y1),(x2,y2),(0,0,255),2)

cv2.imshow('show',img)
cv2.waitKey()

import cv2
import numpy as np
from matplotlib import pyplot as plt

img = cv2.imread('img.jpg')
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
edges = cv2.Canny(gray, 50, 150, apertureSize=3)
lines = cv2.HoughLinesP(edges, 1, np.pi/180,100, minLineLength=100, maxLineGap=10)
for line in lines:
  x1, y1, x2, y2 = line[0]
  cv2.line(img, (x1, y1), (x2, y2), (0,255,0), 2)

cv2.imshow('show',img)
cv2.waitKey()